In general, bent metal tubing has various uses, including providing an underlying structure for greenhouse roofs, tunnels, or canopies. Although these structures are preferably relatively low cost and easy to construct, the difficulty of bending metal tubes appropriately and efficiently has led to such structures being both expensive and labor intensive to construct.
The most commonly used method to bend metal tubing is through the use of a tubing roller. A tubing roller generally consists of a large wheel with a hand crank. The metal tube is placed in a cavity at the bottom of the large wheel, and the user must then crank the wheel using the hand crank in order to shape the tubing (with the tubing passing through the roller multiple times, depending on the desired radius). This method, however, is very inefficient, as it requires a large amount of physical labor and is very time-consuming.
Another common method for bending metal tubing is utilizing a three roll bender, which generally consists of three smaller wheels and a hand crank. Specifically, a metal tube is generally placed within a gap located between the three wheels and, like above, the hand crank is cranked in order to shape the tubing. Depending on the desired radius, the tubing is typically passed through the bender multiple times. The three roll bender may also comprise an electric motor, which may replace the hand crank, thereby making the bending task less labor intensive. Although both variations of the three roll bender are less labor intensive than the tubing roller, they are both overly time intensive methods for bending metal tubing.
As discussed above, the two prior methods are generally very time intensive and thus are not usually conducive to bending large quantities of tubing. Although it has been suggested to heat the metal tubes to increase efficiency (by decreasing the tubes' stiffness), safety risks raise a concern as a heater must be positioned at a location where the tube is bent.
U.S. Pat. No. 6,931,908, issued to Mitson (“Mitson”) discloses a tube bending device comprising two clams, a center die, hydraulic motor, and base. The single center die is configured to push against the metal sheet to bend the metal into the shape of the center die. Because the Mitson reference discloses a tube bending device comprising only a single part that moves in order to bend the tubes, the Mitson bending method does not generally allow users to create dogleg bends, which are generally sharp bends in an otherwise smooth curve.
Similarly, U.S. Pat. No. 3,025,904, issued to De Marco (“De Marco”) and U.S. Pat. No. 2,459,132, issued to Nielson (“Nielson”) disclose bending devices which comprise a center die that is pushed or pressed against a piece of metal secured at two ends. Like the Mitson reference, the De Marco and Nielson references do not allow a user to create dogleg bends. Additionally, the bending devices disclosed in these references are inefficient, as they require a substantial amount of time to install the metal tubing into the bending device.
U.S. Pat. No. 2,527,412, issued to Green (“Green”) discloses a bending device which uses two rocker members and wings, which move downward and outward with a centered die. U.S. Pat. No. 1,315,937, issued to Artz (“Artz”) discloses a bending device which uses a ram instead of a die to form bends in metal. Like the De Marco, Nielson, and Mitson references, the bending devices disclosed in the Green and Artz references require an ample amount of time to install a metal tubing for bending.
Therefore, based on the foregoing, what is needed is a bending device that is quick and efficient in bending metal tubes. Preferably, the new and improved bending device will also allow the user to create secondary bends such as dogleg bends.